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Systematics Section / ASPT

Knapp, Wesley [1].

The Taxonomy of Juncus longii, a putative taxon within the Juncus marginatus Complex (Juncaceae sect. Graminifolii).

The taxonomic status of the southeastern U.S. species Juncus longii has been debated almost since its first description in 1937. Taxonomic treatments of the Juncus marginatus complex vary widely. Treatments by Radford et. al (1968) and Fernald (1950) recognize three species (Juncus biflorus, J. longii and, J. marginatus), whereas other treatments such as Brooks in the Flora of North America (2000) recognize only one species, J. marginatus. My field and herbarium studies cover most of eastern North America. The number of specimens located in the field and in herbaria suggests J. longii is a globally rare species with a known range of Maryland, Virginia, the Carolinas, and Mississippi. Preliminary univariate and multivariate statistical analyses of twelve morphological characters suggest that Juncus longii is a species distinct from Juncus marginatus and Juncus biflorus, with all three species being identifiable by a number of characters. Ecological differences are also apparent. Juncus longii is restricted to early successional seepages with exposed sandy soils. Juncus marginatus and J. biflorus, however, are found in less specialized habitats. I have documented syntopic occurrences of Juncus longii with J. marginatus and J. marginatus with J. biflorus, suggesting the morphological differences used to identify these species are not a reflection of environmental conditions. By elucidating the taxonomic status and ecology of Juncus longii, the geographic range and conservation status of this species may be clarified.


1 - 101 Whiteleysburg Rd., Greensboro, Maryland, 21639, United States

Keywords:
Juncus longii
Juncaceae
morphology
Conservation Concern
PCA.

Presentation Type: Paper
Session: 20-2
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 2:00 PM
Abstract ID:736


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